Basic W CMP Requirements and

FIGURE 9.5 A typical testing wafer for tungsten plugs (from Ref. 13). 

Robotically Loading the wafer onto the polishing head. 

Prepolishing to saturate the pad with the slurry using dummy wafers. 

Robotically loading the wafer onto the cleaning stations. 

The slurry distribution and mixing system operates in the background of the actual wafer processing. However, a slurry with consistent physical and chemical properties is critical for maintaining a repeatable W CMP process with steady yield. Two of the most important parameters to monitor are etchant (oxidizer) and solid (abrasive particle) concentrations. 

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